SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b633789a3259a5fa9624a8d74a1a49d30cfd98b156a00b28c89060c0f2d18fff' 
  AND token = 'c7C/ea7Va51LgN/kv9DJ3wjJTDK8xs4ZvpgPSq6E2d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}